Vertical axis turbine

Abstract

A vertical axis turbine and method of making same is disclosed. The device and method comprise a plurality of blades rotatably disposed around an axis of rotation at a plurality of blade locations, each blade being twisted at a first angle about its longitudinal axis, each blade having its distal ends located a predetermined distance from the axis of rotation, each blade being bent at one or more central locations along the longitudinal axis so the one or more central locations are the same predetermined distance from the axis of rotation as the distal ends, each blade having a foil cross section perpendicular to the axis of rotation for maintaining unidirectional rotation of that blade about the axis of rotation in a fluid flow, and each blade having its longitudinal axis tilted at a second angle with respect to the axis of rotation.

1. A vertical axis turbine comprising a plurality of blades rotatably disposed around an axis of rotation at a plurality of blade locations, each blade being twisted at a first angle about its longitudinal axis, each blade having its distal ends located a predetermined distance from the axis of rotation, each blade being bent at one or more central locations along the longitudinal axis so the one or more central locations are the same predetermined distance from the axis of rotation as the distal ends, each blade having a foil cross section perpendicular to the axis of rotation for maintaining unidirectional rotation of that blade about the axis of rotation in a fluid flow, and each blade having its longitudinal axis tilted at a second angle with respect to the axis of rotation, wherein the second angle is approximated by the equation
   β=sin−1[2 r ·sin(π/ n )/Length],
 
 wherein β is the second angle, r is the predetermined distance from the axis of rotation, n is the number of blade locations, and Length is the length of the longitudinal axis of each blade, or one or more blades, at each blade location. 
 
     
     
       2. The vertical axis turbine of  claim 1 , further comprising
 a plurality of attaching means attaching at least the distal ends of each of the plurality of blades to a rotating shaft at the axis of rotation. 
 
     
     
       3. The vertical axis turbine of  claim 1 , wherein
 the first angle is approximately 360° divided by the number of blade locations. 
 
     
     
       4. The vertical axis turbine of  claim 1 , wherein
 the second angle results in a top distal end of each blade being directly above and behind a bottom distal end of a blade in a succeeding blade location. 
 
     
     
       5. The vertical axis turbine of  claim 1 , wherein
 the foil cross section is symmetrical or asymmetrical. 
 
     
     
       6. The vertical axis turbine of  claim 1 , wherein
 a direct drive generator is disposed between the plurality of blades at the axis of rotation. 
 
     
     
       7. The vertical axis turbine of  claim 6 , wherein
 the direct drive generator is used as a flywheel to maintain momentum of the plurality of blades when fluid flow decreases.